So I did a little experiment today that I've been meaning to do for a while. I've been recording my bass tracks through the SPDIF outs of my Line6 Bass POD xt-pro to my digi 002r. Today I decided to record the analog out simultaneously. I'm not completely familiar with the block diagrams of either machine, but I assume that the biggest (if not the only) difference between the two tracks should be that the digital direct eliminates two conversions. So to hear the difference I inverted one signal and nudged the analog forward to correct for the slight latency. This lets me hear the actual difference (which is pretty significant) and balance the volumes by finding the spot where the difference has lowest volume. As you would expect the difference is all in the high end. The solo analog signal is not at all unpleasant - the high frequency roll off sounds pretty nice in this particular riff (I was working on the intro to So What). But the difference is definitely audible - though I'm always a little suspicious of non-blind tests like this. Can anyone suggest (inexpensive) ways that I could improve this experiment? Things I should be listening for in order to understand digital conversion artifacts?